Electrical fuel control system for internal combustion engines

ABSTRACT

An electrical control system with a plurality of sensors, shifted code setting circuits, selecting means, adders, memories and a command signal generator causing output signals of the sensors to be respectively binary-coded, shifted by the shifted code setting circuits and selected in accordance with the output signals of the sensor corresponding thereto in the manner previously programmed, for developing respective output signals which are added in a time-sharing manner controlled by the command signal generator to obtain an engine control signal to secure the optimum engine condition.

United States Patent Yoshida et al.

ELECTRICAL FUEL CONTROL SYSTEM FOR INTERNAL COMBUSTION ENGINESInventors: Hiroshi Yoshida; Noriyoshi Ando;

Kazuo Oishi, all of Kariya, Japan [73] Assignee: Nippondenso Co., Ltd.,Kariya,

Japan Notice: The portion of the term of this patent subsequent to June1 l, 1991, has been disclaimed.

[22] Filed: Feb. 20, 1974 21 Appl. No.: 444,170

Related US. Application Data Continuation-impart of Scr. No. 327,603,Jan. 26, 1973, Pat. No. 3,816,717, which is a continuation of Ser. No.126,830, March 22, 1971, abandoned.

1*Sept. 16, 1975 [56] References Cited UNITED STATES PATENTS 3,749,0707/1973 Oishi 123/32 EA 3,756,204 /1973 Suda 123/32 EA 3,796,197 3/1974Locher et a1. 123/32 EA 3,811,037 5/1974 Kitano 235/150.21

OTHER PUBLICATIONS Williams: Electronic Fuel Injection Reduces Automotive Pollution, Electronics, Sept. 1972, Vol. 45, No. 19, pp. 121425.

Primary Examiner-Felix D. Gruber Attorney, Agent, or F irm-Cushman,Darby & Cushman [5 7] ABSTRACT An electrical control system with aplurality of sensors, shifted code setting circuits, selecting means,adders, memories and a command signal generator causing output signalsof the sensors to be respectively binary-coded, shifted by the shiftedcode setting circuits and selected in accordance with the output signalsof the sensor corresponding thereto in the manner previously programmed.for developing respective output signals which are added in atime-sharing manner controlled by the command signal generator to obtainan engine control signal to secure the optimum engine condition.

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1. A control system for an internal combustion engine comprising: firstsensor means for producing a first digital signal responsive to a firstparameter of the engine condition, first discriminating means, connectedin circuit with said first sensor for detecting one of a plurality ofpredetermined first parameter ranges which includes said first parameteras represented by said first digital signal, and producing a number ofoutput signals as determined by said detected first parameter range;second sensor means for producing a second digital signal responsive toa second parameter of the engine condition, second discriminating meansconnected in circuit with said second sensor for detecting one of aplurality of predetermined second parameter ranges which includes saidsecond parameter as represented by said second digital signal, andproducing a number of output signals as determined by said secondparameter ranges; shifted code setting circuit means for shifting aninput digital code signal applied thereto, selecting means connected tosaid first and second discriminating means for selecting an input signalapplied thereto in accordance with the output signals of said first andsecond discriminating means, first circuit means connected to said firstand second sensor means and including said shifted code setting circuitmeans and said selecting means for producing coded digital signals incodes which are obtained by subjecting said first and second digitalsignals to shifting and selecting operations by said shifted codesetting circuit means and said selecting means in accordance with theoutput signals of said first and second discriminating means, secondcircuit means, connected to said first circuit means and including anadder and a memory, for producing a digital control signal by adding thecoded digital signal outputs of said first circuit means; command signalgenerating means, connected to said second circuit means, for producingcommand signals to control a setreset operation of said memory in thetime sharing manner, third circuit means connected to said secondcircuit means for producing a drive signal in accordance with saiddigital control signal of said second circuit means; and electricallyactuating means connected to said third circuit for operating inaccordance with the drive signal of said third circuit means.
 2. Acontrol system for an internal combustion engine according to claim 1,wherein said first discriminating means comprises a plurality ofdiscriminators connected to said command signal generating means fordetermining whether the first digital signal of said first snesor meansis greater or smaller than a predetermined value in response to saidcommand signals.
 3. A control system for an internal combustion engineaccording to claim 1, wherein said selecting means of said first circuitmeans comprises a plurality of logical elements connected to said firstand second discriminating means and a plurality of gate means connectedto said shifted code setting circuit means of said first circuit means.4. A control system for an internal combustion engine according to claim1, wherein said first and second digital signals of said first andsecond sensor means are produced in a binary code of a predeterminednumber of places.
 5. A control system for an internal combustion engineaccording to claim 4, wherein said shifted code setting circuit meansproduces digital signals in binary codes which indicate respectivelynumbers represented by binary codes oBtained by shifting said binarycode of one of said first digital signal and second digital signal tothe right successively by one place each shift.
 6. A control system foran internal combustion engine according to claim 1, wherein said commandsignal generating means comprises a clock pulse generator, a flip-flopcircuit connected to said clock pulse generator for dividing the timecycle of the clock pulse of said clock pulse generator, and logicalcircuit means connected to said flip-flop circuit.
 7. A control systemaccording to claim 1, wherein said third circuit means comprises: amemory circuit connected in circuit with said second circuit means forretaining said digital control signal of said second circuit means; anangular sensor for periodically producing pulses in accordance withrotations of the engine a timing sensor for producing a timing pulseresponsive to a predetermined position each cycle of each cylinder; acounter for counting pulses of said angular sensor transmitted theretoand producing an output digital signal of binary code corresponding tothe count a comparator for producing said drive signal upon coincidenceof said digital signal of said memory circuit and that of said counter;a distributor comprising means responsive to said timing pulse forpermitting said pulses of said angular sensor being transmittedtherethrough to said counter.
 8. A control system for an internalcombustion engine according to claim 7, wherein said first parametersensed by said first sensor means is intake manifold vacuum, said secondparameter sensed by said second sensor means is speed of the engine andsaid electrically actuating means is an ignition system.
 9. A controlsystem for an internal combustion engine according to claim 1, whereinsaid third circuit means comprises; a memory circuit connected incircuit with said second circuit means for retaining said digitalcontrol signal of said second circuit means; a clock pulse generator forproducing clock pulses with a predetermined frequency; means forproducing a timing pulse which determines the starting of fuel injectionduring each cycle for each cylinder; a counter for counting said clockpulses transmitted thereto and producing an output digital signal in abinary code corresponding to the count; a comparator for producing anoutput signal for ending the operation of said electrically actuatingmeans under coincidence of the digital signal retained in said memoryand that of said counter, and a distributor including means responsiveto said timing pulse for starting and continuing operation of saidelectrically actuating means and simultaneously permitting said clockpulses being transmitted to said counter from said clock pulse generatorto pass therethrough and means responsive to an output signal of saidcomparator for ending the operation of said electrically actuating meansand simultaneously preventing thereafter said clock pulse from beingtransmitted to said counter.
 10. A control system according to claim 9,wherein said first parameter sensed by said first sensor means is intakemanifold, said second parameter sensed by said second sensor means isthe acceleration of the engine and said electrically actuating means isan electromagnetic valve for injecting fuel into the engine.
 11. Acontrol system according to claim 1, wherein said first sensor meanscomprises vacuum sensor means for producing a signal responsive to theintake manifold vacuum, said second sensor means comprises speed sensormeans for producing a signal responsive to the speed of the engine, saidelectrically actuating means comprises an electromagnetic valve forinjecting fuel into the engine and an ignition system for producing anignition spark of the engine, and said third circuit means comprisesinjection circuit means having first selector switch means forenergizing said electromagnetic vaLve and ignition circuit means havingsecond selector switch means for energizing said ingition system; saidcontrol system further comprising selection signal generating meansconnected to said first and second switch means for controlling thetransmission of said digital control signal of said second circuit meansto said injection circuit means and to said ignition circuit means.